Audio Noises (Game Gear)
The Game Gear can have several causes of noise fairly easily introduced.
This article will cover common fixes and work arounds for versions of the CleanJuice, CleanScreen and CleanAmp products to get the best audio quality if you experience noise.
The inductor on the Game Gear filtering the audio 5V rail actually makes things worse if the amp uses too much current, mainly noticeable on CleanAmp Duo (due to audio tone range and current pull).
It is recommended for the best fix to replace the audio inductor (L3) with a multilayer or molded inductor (NOT a drum/wire wound) of 10uH to 47uF and 300mA or higher saturation current.
If using a v1 CleanAmp Duo (with 330uF capacitors on the right side instead of 680uF) you will have to add an extra 680uF capacitor to the CleanAmp to prevent audio cut-out.
The new CleanAmp Duo v1.1 (already live, no stock of old version on our store) already has this 680uF capacitor in place so there is no need for the wire bridge.
One main issue I have discovered is in the latest CleanJuice and CleanScreen products I added resettable fuses and current protection circuits. It turns out for whatever reason (still not fully discovered why) but adding these resettable fuses are adding noise to some consoles.
This noise tends to be present overall, and not specific to any action.
So as a general rule of thumb if you get audio noise then start by bridging these resettable fuses on the CleanJuice and CleanScreen if you have them.
If you happen to have a version of the CleanScreen with a super big inductor on, just bridge it, or replace it with a multilayer or molded inductor (NOT a drum/wire wound) of 10uH to 47uF and 300mA or higher saturation current.
The inductor helps reduce noise, however on the revision with the large inductor was of the kind Drum / Wire Wound which actually makes noise not removes it, so it needs removing or replacing with a chip inductor of type Multilayer, Molded or Thin/Thick Film.
Version 3.1 already has this large inductor removed and the chip inductor installed.
Here is an example of using a chip inductor instead of the drum inductor.
Sometimes due to extra mods like IPS screens and amps, the main Game Gear 5V rail needs more capacitance.
Chucking an extra capacitor on the 5V rail helps with noise also if you experience some noise.
The old grey wire harnesses can actually add some noise to the system. If you still get noise after adding the other fixes, it is worth changing these cables.
For all of these fixes above I plan to implement them on the new CleanScreen / CleanAmp / CleanJuice (removing the fuses and using another method, adding extra capacitance to the 5V rail on both the CleanAmp and CleanScreen etc...).
The bridging of the 5V Audio rail on the Game Gear would still have to be done regardless.
Then I also plan to improve further any digital noise coming from the ASIC and RAM with a Dehum kit for pure silence in audio noise like the GBA.